The present invention relates to a digital copier and, more particularly, to a density control system for a digital copier.
In a prior art analog copier, an automatic density control mechanism is so constructed as to erase the background of an original document and, therefore, the density of an image area is reduced to a level which is low enough to erase the background. Consequently, the copy density in the image area is necessarily lowered to prevent a clear-cut copy from being produced. On the other hand, a digital copier allows the background and the image area to be varied in level independently of each other. Hence, an automatic density control mechanism installed in a digital copier should preferably be capable of adjusting the level of image area independently of the level of the background even when the background is erased.